The protagonists are not "punk" but to me the setting contains many elements that I would consider punk. The vast wealth gap, the abandonment of vulnerable populations and the areas they inhabit, and the seedy underbelly of the cities all lurk underneath the gleaming chrome and neon surface. To me this is the epitome of the genre, the incongruity between the powerful corps and their government puppets and the misery of the general population. GitS feeds the dream of super wizard class hackers and street samurai but also pays homage to the downtrodden masses left behind by progress. With a nice dash of philosophy.